Minor Thermal Burns

Key Practice Points

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The first responsibility of a clinician when evaluating a burn patient is to ensure that there is no airway involvement, inhalation injury, associated trauma, constricting burn, or large burn with potential fluid loss.

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The first treatment step of a minor burn is to cover it with a cool (not cold) wet cloth to stop continued thermal injury and to relieve pain.

Signs of inhalation injury include cough, shortness of breath, singed nasal hair, and soot in the mouth or nasal passages.

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The extent of burn is measured by the total area of second-degree and third-degree burns. First-degree burns do not count in that determination.

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Patients with second-degree burns covering <15% of the body surface area can be treated as outpatients.

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Intact blisters act as good burn dressings and do not always need to be removed.

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Burn dressings should be nonadherent so that delicate epidermal and dermal cells will not be torn off during dressing changes.

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Burned patients are at risk for tetanus, and patients’ inoculations should be up to date, or patients should receive boosters at the time of treatment.

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There is no evidence that prophylactic oral antibiotics are necessary for minor burns treated on an outpatient basis.

The treatment of burns is a common activity for personnel in facilities that care for emergency wounds and injuries. A thorough understanding of the treatment requirements of burns is necessary for proper selection of patients who can be managed appropriately on an outpatient basis and for selection of patients who need referral for specialized care. The depth, type, and extent of the burn; the anatomic location; and the underlying patient condition all are important factors in making the treatment decision. Although individual treatment aspects of minor burns remain controversial, basic management principles do not vary greatly. The three main principles for treating burn patients are (1) relief of pain, (2) prevention of additional infection and trauma, and (3) minimization of scarring and contracture.

Initial Management and Patient Assessment

No matter how small or how trivial a burn appears, the patient must be assessed for more severe associated problems and injuries. If the patient sustained the burn at the scene of a fire or explosion, immediate evaluation for inhalational injury, carbon monoxide exposure, cyanide exposure, and other trauma is mandatory. Inhalational injury is the most common cause of mortality in fire victims. Clinical signs of inhalational injury include burned nasal hairs, soot on the face, hoarseness, coughing, shortness of breath, and wheezing. Even if these signs are not present at the outset, an inhalational injury must be suspected in patients who were trapped in an enclosed, smoke-filled space. Respiratory tract injury often is delayed, and observation of the patient for 24 hours may be indicated. Carbon monoxide exposure is suspected in any patient who is alert and has a headache or in a patient with confusion or other alteration of mental status.

When the patient has been initially stabilized, when vital signs have been taken, and when unnecessary articles of clothing have been removed from the burned area, attention can be turned to the burn itself. The most salient clinical symptom of minor burns is pain. Epidermal (first-degree) and superficial partial-thickness (superficial second-degree) burns can be extremely painful and require immediate pain relief. The simplest and most rapid manner in which to abolish burn pain is to place moist, cool towels over the burned area. Clinical and experimental evidence shows that the cooling of burned surfaces can decrease the eventual damage to burned tissues. The water should not be very cold because excessive cold can compound the burn injury. A water temperature of 8°C (45°F) to 23°C (75°F) seems to be optimal to obtain pain relief and some measure of protection for burned tissue.

Cooling can be effective for 3 hours postburn. In a study of children with burns, it was found that only 22% received adequate first aid, including cooling. Immediately on arrival at the care facility, cooling should be initiated to abort the continuing tissue injury. Care must be taken to ensure that large burn areas are not covered with cool, moist towels for excessive periods, because hypothermia can set in. In addition to cool towels and sponges, parenteral pain medicine, such as morphine sulfate or meperidine, can be used, especially for patients who have a significant component of anxiety associated with their burns.

While the patient is being stabilized and pain relief is being administered, a thorough history is taken. Important items in the history include the age of the patient, any associated conditions and illnesses, psychosocial considerations, and drug allergies. Patients younger than 2 years old have thin dermis and immature immune systems. These children rarely are treated on an outpatient basis. Likewise, patients older than 65 years tolerate burns poorly and often need inpatient care. Patients with underlying diseases, such as diabetes, pulmonary disease, severe cardiac problems, and disorders requiring long-term immunosuppressive therapy, are at higher risk for additional complications with burns, and these patients require special consideration from hospital management.

Frequently, burn victims have significant psychosocial problems. Similar to automobile trauma victims, burn victims often have alcohol-related or drug-related disorders. Although these impairments may have nothing to do with the treatment of the burn itself, severe alcohol or drug dependency may preclude outpatient management, even for minor burns. The worst psychosocial problem associated with burns is child abuse. Experienced burn care personnel see this catastrophe frequently and tend to think of all children with burns as potential victims of child abuse until proved otherwise. Finally, during the history, a thorough detailing of allergies is necessary, because many drugs may be administered or applied to a burn victim during the course of his or her management.

Burn Assessment

Cause of the Burn

Knowing the cause of a burn can make a difference in predicting its depth and extent. Brief scalding burns, which occur with the spilling or splashing of hot water, usually result in epidermal or superficial partial-thickness burns. Burns caused by immersion in a hot liquid or contact with a flame more frequently result in deep partial-thickness or full-thickness burns. These burns can be complicated and serious, especially when important anatomic parts, such as the hands or face, are involved. Electrical burns almost always cause full-thickness injuries at the burn site. In addition, electrical injuries can be associated with muscle necrosis, fractures, and cardiac arrhythmias.

Body Location

The anatomic location of a burn is an important factor in determining management. Because of the complexity and crucial function of the hands, extensive partial-thickness or full-thickness burns on the hands are best managed, at least at the outset, in a controlled setting. Not only do hand burns require careful cleansing, débridement, and dressing, but also there is a danger of joint stiffening secondary to the immobility caused by pain and edema. Patients must observe strict elevation of the burned extremity in addition to early motion exercises to prevent “freezing” of the hand. This freezing complication occurs more frequently in patients older than age 50. Partial-thickness burns of the face not only raise the possibility of airway obstruction and inhalational injury, but they also can be difficult to manage surgically.

Burns of the perineum are technically difficult to manage and are extremely uncomfortable for the patient. It is beyond the capabilities of most patients or families to care for these problems at home. Among the most frustrating burns to manage on an outpatient basis are burns of the foot. The dependent nature of this anatomic part and its weight-bearing function cause frequent failure of outpatient management. It is difficult for patients to maintain voluntarily the necessary strict elevation of the legs, and failure to elevate properly can lead to edema, pain, and tissue breakdown at the burn site.

Epidermal burns (first-degree): These burns are the most common. Heat induces dermal vasodilation, giving the epidermis its characteristic red color. Blistering does not occur, and these burns heal without treatment. The superficial epidermis sloughs or peels about 5 to 7 days after the burn is sustained, and the vasodilation gradually disappears. Sunburn is the most common example of an epidermal burn. Occasionally, if the heat exposure was especially intense or prolonged, what appears to be an epidermal burn blisters and becomes a superficial partial-thickness burn after 12 to 24 hours.

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Superficial partial-thickness burns (second-degree): These burns are so designated because the epidermis and part of the dermis are injured. Superficial partial-thickness burns classically blister and are extremely painful. When the necrotic epidermis is removed, the injured dermis is homogeneously pink and moist in appearance. It is extremely sensitive to touch but heals without scarring over 2 to 3 weeks. The dermis and dermal appendages, such as pilosebaceous units and eccrine sweat glands, survive and give the skin a chance to regenerate epidermis.

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Deep partial-thickness burns (second-degree): Clinically, it is important to distinguish between superficial and deep partial-thickness burns. There are important differences in the time they require to heal and in eventual cosmetic appearance. Deep partial-thickness burns are not as painful to touch, and they appear drier and whiter when débrided. Sometimes the surface of these burns is interspersed with reddish spots, indicating underlying dermal appendages such as sweat glands and hair follicles. There still is some awareness of pinprick, however, and some of the dermal appendages are preserved. New skin can grow from these appendages, but some need supplemental grafts. These burns take longer than 3 weeks to heal.

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Full-thickness burns (third-degree): With full-thickness, or third-degree, burns, the dermis and the dermal appendages are totally destroyed. A dry, taut, leather-like surface that is insensitive to examination or pinprick characterizes the appearance of these burn injuries. The color of these burned areas can vary from white to brown to black. There is frequent difficulty in distinguishing between deep partial-thickness and full-thickness burns on initial presentation of a patient to a wound care facility. Often these two types of burns are treated in the same manner and require grafting for final coverage of the damaged area.

Cross section of skin with illustration of different burn depths, including superficial (1°) to deep thermal (4°).

Extent of the Burn

Proper estimation of the extent of body surface area affected is crucial to burn management. Only partial-thickness (second-degree) and full-thickness (third-degree) injuries are considered in the calculation. The “rule of nines” is adequate for initially estimating burn size in adults ( Fig. 17-2 ). Surface anatomy can be divided into areas that represent 9% or multiples of 9% of the body surface. The head and each arm constitute a 9% surface area apiece, whereas one leg is 18%. The entire surface area of the thorax and abdomen combined, anterior and posterior, is 36%.